Characterization of phospholipid composition and its control in the plasma membrane of developing soybean root
The phospholipid composition of plasma membrane enriched fractions from developing soybean root and several mechanisms which may regulate it have been examined. Plasma membrane vesicles were isolated from meristematic and mature sections of four-day-old dark grown soybean roots (Glycine max (L.) Merr. Cult. Wells II). Analysis of lipid extracts revealed two major phospholipid classes: phosphatidylcholine and phosphatidylethanolamine. Minor phospholipid classes were phosphatidylinositol, phosphatidylserine, phosphatidylgylcerol and diphosphatidylgylcerol. Phospholipid composition was similar at each developmental stage. Fatty acids of phosphatidylcholine and phosphatidylethanolamine were 16:0, 18:0, 18:2, and 18:3. Fatty acid composition varied with both phospholipid class and the developmental stage of the root. The degradation of phosphatidylcholine by endogenous phospholipase D during membrane isolation indicated that this enzyme might be involved in phospholipid turnover within the membrane. Phospholipase D activity was heat labile and increasing the pH of the enzyme assay from 5.3 to 7.8 resulted in 90% inhibition of activity. The turnover of fatty acids within the phospholipids of the plasma membrane was studied. Mature root sections were incubated with (1-/sup 14/C) acetate, 1 mM Na acetate and 50 ..mu..g/ml chloramphenicol. Membrane lipid extracts analyzed for phospholipid class and acyl chain composition revealed that the long incubation times did not alter the phospholipid composition of the plasma membrane enriched fraction.
- Research Organization:
- California Univ., Davis (USA)
- OSTI ID:
- 5942074
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
LIPASE
ENZYME ACTIVITY
PHOSPHOLIPIDS
CHEMICAL COMPOSITION
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CELL MEMBRANES
CHOLINE
GLYCINE HISPIDA
ROOTS
TRACER TECHNIQUES
ALCOHOLS
AMINES
AMMONIUM COMPOUNDS
BACTERIA
CARBOXYLESTERASES
CELL CONSTITUENTS
DRUGS
ENZYMES
ESTERASES
ESTERS
HYDROLASES
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LEGUMINOSAE
LIPIDS
LIPOTROPIC FACTORS
MEMBRANES
MICROORGANISMS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PLANTS
QUATERNARY COMPOUNDS
RHIZOBIUM
550201* - Biochemistry- Tracer Techniques